On the main page of Smtnet towards the end of the opening paragraph states the following...Your " research continues in determining the reliability of thick film hybrid microcircuits and similar technologies using low-temperature, co-fired ceramics. " I was wondering if I should be worried about field failures?..(in the short and/or long term). and is there more concern with the thick film or wire bonds (ball/wedge)?

Yes, one should always be concerned about "field failures" because they represent the point at which the product has exceeded its design lifetime with respect to its service conditions. Hybrid microciruit technolgy (HMC) has been around for a long time so we (the industry) are familar with alot of the "do's and don't's" in terms of design specifications and the appropriate service conditions. Those "do's and don't's" have often been just rules of thumb or "ole" anecdotes. Now, with the come-back of HMC technology as a result of the boom in wireless communications, design margins for such equipment are shrinking in order to meet costs and price guidelines. Therefore, the design engineers must have at their disposal, tools with which to QUANTIATIVELY predict the reliabilty of these products. Sandia research into HMC technology is concerned with developing the computational tools with which to predict the reliabilty of HMC hardware in areas such as intermetallic compound layer growth as well as thermal mechanical fatigue and the application of Pb-free solder technology to HMC product.

Fianlly, I think that wire bonding is in the same "boar" as thick film technology. The industry is comfortable with the technology due to its maturity. However, if new applications of HMC technology (number of bonds required or adverse service contions) are going to push the envelop of wire bonding technology, then this topic will likewise need to be investigated.